Tabulation allows the use of a data item or a constant value as a weighting factor during tabulation. This is particularly useful in the case of a survey, where the weight assigned to each case or observation in the sample must be taken into account in order to produce numbers representative of the whole. If no weight value is specified, weight is assumed to be "1".
In the same fashion, values (rather than counts) may be tabulated; like weights, values are numeric data items or constants with or without decimal positions. When a value is specified for tabulation, the effect is that of cumulative addition of the specified value into the cell at the intersection of the row and column coordinates. If you leave the value item blank, a value of 1 will be added into the appropriate cell during tabulation. Tabulating values can be used, for example, when a variable such as "number of children born" has been collected for each woman in the population and you wish to tally the total number of children born rather than tallying the number of women with a particular number of children. In this case you would use the "number of children" variable as the value to tally so that for each woman, the number of children born to that woman would be added to the appropriate cell.
If both value and weight are specified for a given table, the specified value is first multiplied by the specified weight and the product of this multiplication is then added to the cell in question. This feature is useful in the case where the unit of observation has a weight, and one of the data items to be tabulated is a quantitative value. An example might be a fertility survey, where each female of child-bearing age carries a sampling weight, and where some of the data items might be "Number of children ever born," "Number of children surviving," etc. Tabulation applications easily permits the accumulation of weighted values to provide the total number of children ever born for all females in the sample.
If the weight or value includes decimals, the decimal may be explicit or implicit, but the dictionary definition should reflect the correct situation. The weight may be assigned to just the current subtable, the entire table or all the tables currently defined in the application.
See also: Add Weights to a Table, Tabulate Values Instead of Frequencies